X-ray Fluorescence of Some Egyptian Coins

Transcription

1 International Journal of Pure and Applied Physics. ISSN Volume 8, Number 2 (2012), pp Research India Publications X-ray Fluorescence of Some Egyptian Coins S.A. Abd El Aal 1, W.A. Ghaly 2, H.T. Mohsen 3, A. El Falaky 4 and A.I. Helal 5 1,5 Central Lab. for Elemental & Isotopic Analysis, Nuclear Research Center NRC, AEA Post No , Egypt. 2,3 Central Lab. for Elemental & Isotopic Analysis, Dept. of Accelerators and Ion Sources, Nuclear Research Center NRC, AEA Post No , Egypt. Preparatory Year Deanship, Jazan University, P.O. Box 114, Saudi Arabia 4 Physics Department, Faculty of Science, Zagazig University. *Corresponding Author wghalyjp@yahoo.com Abstract The elemental composition of ancient and modern coins can give significant information on different aspects of life, politics and economy. The purpose of the present work is to identify and study the Egyptian coins in the period ( ) by using Energy Dispersive X-Ray Fluorescence (EDXRF) technique. The elemental composition in a fast and non-destructive way for the Egyptian coins is demonstrated. This technique provides a historical data about the Egyptian economics in the last 100 years. Keywords: X-ray Fluorescence / Non Destructive Analysis/ Multi-elemental Analytical Method. Introduction Energy Dispersive X-ray Fluorescence (EDXRF) technique is among other elemental analytical compositions techniques which are used to study the ancient coins of countries (1,2). It can analyze the ancient coins and gives additional insight prove about the strength states of any nation or empire (3,4). It gives a clear picture of economy and history of any nation during a limited period of age. Also it can be applied to understand the history and the present economy status of certain region or country (5). EDXRF technique is regarded as a non-destructive, fast, sensitive, and capable of simultaneous multi-elemental analysis. Moreover, coins can be quantitatively analyzed without damage and they do not require any special sample preparation as in the most of the other elemental analysis techniques (6).

2 70 S.A. Abd El Aal et al Since coins are connected to the day live activities in the society so the economic values of their metallurgy elemental components can reflect the stability environment of the country at the time of releasing that coin. In the present work, multi-elemental composition analysis of some Egyptian coins namely, 1, 2, 5 and10 piastres, in the last 100 years by using EDXRF are performed. The major and minor elements in the Egyptian coins alloy are discussed. Also an attempt to state the historical data about Egyptian coins during this period is demonstrated. Experimental The coins are placed in ultrasonic cleaner to be washed by distilled water and nitric acid 2.5% and for 5 minutes and then dried with air streaming for 5 minutes. For weighting, the coins are balanced by using a sensitive digital balance. Elemental analysis studies were made on 100 coins being struck during the period ( ). The face and back of 1, 2, 5 and 10 Piastres (Qirshs) coins are shown in Fig. 1. The coins are identified with their international standard catalogue of world coins ( ) 35 th edition (7). Figure (2) represents the schematic diagram of the EDXRF system which is used for the study. The system consists of a low power air-cooled X-ray tube as an excitation source. The operating voltage and the current of the X-ray tube were 30 kv and 0.6 ma, respectively. The X-rays from the tube was exposed on a molybdenum secondary exciter and the generated characteristic X-rays of molybdenum were used to excite the elements present in the studied coins samples. The measurement time for the determination of the main components was 300 seconds. The characteristic X-rays emitted from the elements present in each sample were collected using a Si(Li)detector and a PC-based multi-channel analyzer. 1. Piastres (10 Milliemes). 2. Piastres (20 Milliemes)

3 X-ray Fluorescence of Some Egyptian Coins 71 5 Piastres (50 Milliemes). 10 Piastres (100 Milliemes). Figure 1: Some Egyptian Coins made between 1916 and Figure 2: Schematic diagram of the EDXRF system. Results and Discussion 1 Piastre (Qirsh) Coin Since 1917 till 1986 where the end version and use of this coin, the geometrical round shape of 1 Piastre was the same. From 1917 till 1957 coin s weight was 5 ± 0.7 gm and after that from 1967 to 1973 the weight is decreased to 1.7 gm. Then in the period of 1973 to 1977 the coin s weight is increased to 3 ± 0.2 gm and finally it decreased to 2 ± 0.1 gm and stayed at this weight till the end of use of 1 Piastre coin.

4 72 S.A. Abd El Aal et al Figure 3: XRF Spectrum of one piastre coin at the year The elemental composition and concentrations expressed in percentages of 1Piastre Egyptian s coin is given in table 1. Inspection of table 1 shows that the coins since 1917 until 1941 was primarily copper and nickel. Other elements namely, Fe, Zn and Mn were observed with minor concentrations less than 0.5 %. From 1957 to 1960, the copper concentration is increased to 90 ±5 % and the coin becomes copper alloy with low concentration of aluminum. In 1967, the coin became aluminum alloy. After 1973 the material of the coins returned back to be copper alloy with 92 ±1 % and aluminum 6±1 %. It continued with these elemental compositions till the last version of this coin at Table 1: Concentration (in mass %)of various elements in 1 piastre Egyptian s coin. Year Cu Ni Fe Zn Mn Al Si A comparison between the elemental concentrations for different periods may give an indication for the economical situation of the country. From 1917 to 1941, the

5 X-ray Fluorescence of Some Egyptian Coins 73 ratio Cu/Ni indicates a good economical situation because this ratio is almost stable. At 1957, Al appeared in the coin alloy and Ni became minor and this means the economy faced some difficulties. At 1967, i.e. at the wartime, the coin was Al alloy which reflects a bad economical situation and the political situation faced unpleasant occurrence. Also the price of Cu on world markets rose to a point where the metallic value of the U.S. cent was almost equal to its face value. (8). Figure (4) shows the increase of the Cu price in U.S. and world markets after 1968 (8). After 1973, the 1Piastre Egyptian s coin was Cu/Al and its ratio became stable till 1984 at the end of use of this coin. Figure 4: U.S. price changes of Cu from 1959 to (Ref..8) In 1973, the price of copper on world markets rose to a point where the metallic value of the cent was almost equal to its face value (8). So in 1974 aluminum cent was appeared (9). 2 Piastres (Qirshs) Coin 2 Piastres weight were changed from 1944 to 1984 which started at 1944 with 2.5gm then increased to 5.6gm at 1954 and after that in it decreased to 5gm at 1973 then at the end it reached to 3.2gm at 1984.

6 74 S.A. Abd El Aal et al Figure 5: XRF spectrum of two piastres coin at the year The elemental composition of the 2 Piastre Egyptian s coin is given in table 2. As shown in this Table, the coin was primarily copper and silver alloy. Another elements Fe, Zn and Al were observed but with minor concentration less than 0.8 %. At 1958 the copper concentration increased to 91 ±0.5 % and the coin became copper alloy with low concentration of zinc 8 ±0.3 %. Finally from 1980 till 1984 the copper concentration increased to 93 ±0.9% while zinc concentration decreased to 5 ±0.8 %. Table 2: Concentration (in mass %)of various elements in 2 Piastres Egyptian s coin. Year Cu Ni Fe Zn Al Ag Mn Si Piastres (Qirshs) Coin 5 Piastres weight were changed from 1956 to The coin s weight started with 3.35gm at 1956 then increased to 4.4 ±0.2gm from 1967 till 1990 became 3.1 gm and finally at 2004 it reached 2.07gm.

7 X-ray Fluorescence of Some Egyptian Coins 75 Figure 6: XRF Spectrum of five piastres coin at the year The elemental compositions of the 5 Piastre Egyptian s coin are given in table3. This Table shows that the coin was primarily silver and copper alloy. In the period of 1967 to 1980 the coin became copper and nickel alloy with concentration 74 ±0.6 % and 24 ±0.6 %, respectively. Other elements such that Fe, Zn, Mn and Co were observed but with minor concentration less than 0.5%. Finally from 1992 till 2004 the copper concentration increased to 93.5±0.5 % and the coin became copper alloy with low concentration of Aluminum 6 ±0.5 %. Table 3: Concentration (in mass %)of various elements in 5 Piastres Egyptian s coin. Year Cu Ni Fe Zn Mn Co Al Pb Ag

8 76 S.A. Abd El Aal et al 10 Piastres (Qirshs) Coin 10 Piastres weight showed some changes from 1960 to 1992 the coin s weight started with 6.95gm at1960 then decreased to 6 ±0.5 gm at 1967 and the weight fixed around this value till 1992 the weight decreased to 4.8 gm. Figure 7: XRF spectrum of ten piastres coin at the year The elemental compositions of the 10 Piastre Egyptian s coin are given in table 4. This Table shows that, the coins were copper and nickel alloy. Another elements such that Fe, Zn, Mn and Co were observed but with minor concentration less than 0.4 %. In 1992 the copper concentration increased to 91.3 %. Nickel replaced with aluminum of 8.4 % and Si with minor a concentration of 0.5 %. Table 4: Concentration (in mass %)of various elements in 10 Piastres Egyptian s coin. Year Cu Ni Fe Zn Mn Co Al Mg Ag Si

9 X-ray Fluorescence of Some Egyptian Coins The elemental compositions of the most public used Egyptian coins in the last 100 years were good indicator for the economical situation of the country. Cu and Ni elements were the basic elements in the coin alloys. Al element starts to appear clearly in the one piaster coin at 1957 and be the major element at Cu element returned to be the major element again at Al element appeared in the two piaster coins at 1984 and in five and ten piaster coins at This could be understood that the Egyptian economy was affected before and after the 1973 war time. Moreover, the presence of some elements in the coin could be regarded as an indicator to the daily life economy of Egypt in the period of 1917 to The Egyptian economy in the last 100 years can be divided into four periods. The first one was before 1950 when Egypt had a good economy. The second interval was till 1973, at this time it was the begging of the failure of economy situation due to the war situation. The third period was till 1984 in which the economy tried to be improved and the last time interval was till 2008, which showed unstability in the situation of the economy and the social life in Egypt. References [1] Constantinescu, B., Bugoi, R., Oberlander, T. E., Parvan K., 2005, Some Considerations on X-ray Fluorescence Use in Museum Measurements, Romanian Reports in Physics, 57(4), pp [2] Hajivaliei, M., Garg, M. L., Handa D.K., Govil K.L., Kakavand T., Vijayan V., Singh K.P. and Govil I. M., 1999, PIXE analysis of ancient Indian coins, Nucl. Instr. and Meth. B, 150, pp [3] M. M. Al- Kofahi and K. F. Tarawneh, 2000, Analysis ofayyubidand Mamluk Dirhams UsingX-Ray Fluorescence Spectrometry, X-Ray Spectrom. 29, pp [4] Z. Sándor, S. Tölgyesi, I. Gresits,, M. Káplán-Juhász, 2000, Qualitative and Quantitative Analysis of Medieval Silver Coins by Energy Dispersive X-Ray Fluorescence Method, Journal of Radioanalytical and Nuclear Chemistry, 246(2), pp [5] C. Vlachou, J.G. McDonnell, R.C. Janaway, 2002, Experimental investigation of silvering in late Roman coinage, Mat. Res. Soc. Symp. Proc., 712, pp II9.2.1-II9.2.9.

10 78 S.A. Abd El Aal et al [6] V. Vijayan, T.R. Rautray and D.K. Basa, 2004, EDXRF study of Indian punch-marked silver coins, Nucl. Instr. and Meth. B; 225, pp [7] C. R. Bruce and Th. Michael, 2008, Standard Catalogue of World Coins ( ) 35 th Official Edition, pp [8] D. Edelstein, 1998, Metal Prices in the United States, U.S. Geological Survey (USGS), minerals publications copper, pp [9] DeLorey, Tom, Nov. 2005, Certified 74 Aluminum Cent, COINage Magazine,. pp 34.